The invention relates generally to biocidal compositions and methods of their use for the control of microorganisms in aqueous and water-containing systems. The compositions comprise a hydroxymethyl-substituted phosphorus compound and 2-(decylthio)ethanamine.
Protecting water-containing systems from microbial contamination is critical to the success of many industrial processes, including oil or natural gas production operations. In oil and gas operations, microorganism contamination from both aerobic and anaerobic bacteria can cause serious problems such as reservoir souring (mainly caused by anaerobic sulfate-reducing bacteria (SRB)), microbiologically influenced corrosion (MIC) on metal surfaces of equipment and pipelines, and degradation of polymer additives.
Biofilm, formed by microorganism growth, can create even greater problems and potentially causes huge economic losses in industry through equipment and pipeline corrosion, system plugging, product failing, and energy losses. Biofilm is formed by a buildup of layers of microorganisms occupying a structured community encapsulated within a self developed polymeric matrix. Microorganisms within the biofilm are known as sessile microorganisms, whereas free floating non-biofilm microorganisms are planktonic.
By growing in biofilms, sessile microorganisms are more tolerant to antimicrobial treatment and biocides that are effective against planktonic microorganisms may not exhibit equivalent efficacy against sessile bacteria inside a biofilm. Moreover, even biocides that are effective against biofilm-associated microorganisms are not necessarily efficient at removing a biofilm from a contaminated surface. The physical presence of the remnants of the biofilm (e.g., exopolysaccharides and dead bacteria cells) still plug systems and oil/gas reservoirs, and lead to an uneven availability of oxygen to e.g., a metal surface that allows corrosion to occur. Thus, killing microorganisms in a biofilm without removing the biofilm from a surface may not always solve the contamination problem.
The problem addressed by this invention is the provision of biocides that are effective against a wide range of microorganisms, that may be used in reduced amounts so as to be economically and environmentally attractive, and/or that exhibit the ability to remove biofilm.